//Use instruction:
//Please enter a valid mathematical expression.
//Examples-
//
//Good:
//(1+3)*7)-(2)
//1-2*3+(6*2)
//
//Bad:
//12--3
//12/0

#include "Stack.h"
#include<math.h>
#include<string>

#define TO_INT '0'

class eval
{
	Stack m_num_stack,m_op_stack;
public:
	void InfixToPostfix(string str);
	int StackPriority( ItemType op);
	int InputPriority( ItemType op);
	void Eval();
	int StrToInt(string str);
	int Compute(char op,int num2, int num1);
};